Transcriptional regulation of the carbohydrate metabolism of the facultatively heterotrophic crenarchaeote Thermoproteus tenax

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The proposed project focuses on the transcriptional regulation of genes encoding the enzymes of the central carbohydrate metabolism of the facultative heterotroph crenarchaeote Thermoproteus tenax. The studies should provide insight into the genetic control mechanisms, which govern the selection of the EmbdenMeyerhof-Parnas (EMP) pathway, the Entner-Doudoroff (ED) pathway, the pentose phosphate (PP) pathway and the oxidative tricarboxylic acid cycle (TCA) for catabolism and determine the direction of the carbon flux through the reversible routes of EMP pathway and TCA cycle in dependence of growth conditions. Our principal aim is to identify regulatory transcription factors, which primarily affect the transcription initiation of genes involved in the central carbohydrate metabolism in response to a carbon source, and to characterize their regulatory effects. As model targets of our investigations, we chose the already characterized genes of the reversible EMP pathway, which show differential mRNA expression under autotrophical and heterotrophical growth conditions. For analyzing the regulatory effects on the transcription initiation, the DNA-binding sites of identified factors will be localized and their specific interaction with their target sites will be determined. Their role in the global control of the central carbon metabolism will be investigated by extending the studies to differentially expressed genes of the other pathway, identified by the ongoing T. tenax genome project.